An electric motor is known in the art, according to which a motor control unit is coaxially arranged with the electric motor. In an electric motor, for example, as disclosed in Japanese Patent Publication No. 2010-028925, a motor control unit is attached to a cover member, which is fitted to fitting portions formed on a motor housing so as to coaxially arrange the motor control unit with the electric motor.
In the above prior art (JP 2010-028925), the motor control unit is arranged in the cover member fitted to the motor housing in a faucet joint structure. An axial position of the cover member is positioned by a flanged portion, which is made of a thin metal plate and formed at the motor housing. According to the above structure, mechanical strength in the axial direction of the electric motor is not large.
In a case that the cover member or another member fixed to the cover member is brought into contact with the motor housing at its whole surface area for the purpose of increasing the mechanical strength, it is difficult to uniformly bring the cover member into contact with the motor housing at the whole surface area in view of processing accuracy and so on. As a result, noise may be generated by vibration or the like.